Drafting frame

ABSTRACT

A DRAFTING FRAME FOR FIBROUS MATERIAL HAVING A SERIES OF NIPPED PAIRS OF DRAFTING ROLLS WHICH ARE DRIVEN AT PROGRESSIVELY HIGHER SPEEDS WITH A SINGLE CENTRALLY LOCATED BACKUP ROLL BEING PROVIDED FOR EACH OF THE SLOWER SPEED DRAFTING ROLLS AND WITH A PAIR OF ARCUATELY SPACED BACKUP ROLLS BEING PROVIDED FOR EACH OF THE HIGHER SPEED DRAFTING ROLLS.

Jan. 12, 1971 ANDERSON 3,553,792

DRAFTING FRAME Original File d March 8, 1967 3 Sheets-Sheet 1 J. .12,1971 R. D. ANDERsON DRAFTING FRAME Original F'ilegl March '8. 1967 3Sheets-Sheet 2 lan.12,1971 R. D.ANDERVSON 3,553,792

DRAFTING FRAME Original Filed March 8, 1967 3 Sheets-Sheet 5 UnitedStates Patent O 3,553,792 DRAFTING FRAME Richard D. Anderson, Neenah,Wis., assignor to Kimberly-Clark Corporation, Neenah, Wis., acorporation of Delaware Continuation of application Ser. No. 621,608,Mar. 8,

1967. This application Dec. 13, 1968, Ser. No. 800,308

Int. Cl. D01h 5/74 U.S. Cl. 19258 4 Claims ABSTRACT OF THE DISCLOSURE Adrafting frame for fibrous material having a series of nipped pairs ofdrafting rolls which are driven at progressively higher speeds with asingle centrally located backup roll being provided for each of theslower speed drafting rolls and with a pair of arcuately spaced backuprolls being provided for each of the higher speed drafting rolls.

This is a continuation of my copending application Ser. No. 621,608,filed Mar. 8, 1967, now abandoned.

BACKGROUND OF THE INVENTION The invention relates to drafting frameshaving pairs of fluted nipped drafting rolls between which a series ofslivers of fibrous material may be passed. In drafting equipment of thistype, pairs of aligned top and bottom fluted drafting rolls are heldtogether in nipped engagement under predetermined amounts of pressure asthe fibrous material passes between them, and these rolls are driven bygearing at progressively faster speed so that the slivers of fibrousmaterial are laterally spread out into the form of a thin web and sothat, at the same time, the fibrous material passing between the rollsis stretched or drafted to more perfectly align the fiberslongitudinally of the thin web.

In equipment of this type, the lengths of the drafting rolls determinesthe width of the thin fibrous web that may be formed by the draftingrolls. The drafting rolls, depending on the type of fibrous materialutilized, are quite small in diameter, such as on the order of twoinches, for example; and as the width of the web desired and the lengthof the drafting rolls are increased, the drafting rolls becomerelatively flexible so that the nip pressure between the drafting rollsundesirably varies from end to end of each pair of drafting rolls. Thedistances between the flutes in the drafting rolls peripherally of therolls, therefore, the diameters of the drafting rolls, as well as thedistances between the pairs of drafting rolls, are dependcut on thelength of the individual fibers in the fibrous material; and, therefore,at least for some types of fibrous material, it is not possible toincrease these dimensions while yet securing the desired stretching ordrafting of the fibrous material and the desired lateral spreadingaction which causes individual slivers being fed into the drawingapparatus to be spread out into a relatively uniform thin web of fibrousmaterial. It is thus not possible to overcome such flexing of longdrafting rolls simply by increasing the diameters of the drafting rolls.

There is a different problem with respect to the relatively slowrotating drafting rolls, which are the rolls acting first on theslivers, than there is with respect to the faster rotating draftingrolls, which are the last rolls in the drafting frame acting on thefibers. There is quite a heavy thickness of sliver passing between theslow rotating drafting rolls; and, therefore, the principal problem issimply a static flexing problem, with the slow rotating rolls beingforced apart by the relatively thick slivers.

The thickness of sliver between the relatively fast drafting rolls isconsiderably reduced, since each pair of drafting rolls reduces thethickness of the slivers and laterally spreads the slivers into a moreuniform web. There, therefore, is no great static force tending to movethe fast rotating drafting rolls apart, but these drafting rolls rathertend to oscillate, flex and whip due to dynamic forces. In a widedrafting frame, each of these fast rotating rolls, being long andlimber, has a critical speed at which it tends to whip; and assumingthat substantial production is desired from the apparatus, this criticalspeed is approached with the fast rotating drafting rolls. The niploading between these fast rotating drafting rolls is very, very slight,due to the small amount of fiber between these rolls, but since thespeeds of these rolls may be very high, these rolls whip, particularlyin their center regions, and thereby produce a fibro s web that isnon-uniform and therefore unsatisfactory.

SUMMARY OF THE INVENTION It is an object of the present invention toprovide an improved drafting frame of this type which is of suchconstruction that the fluted drafting rolls may be maintained undersubstantially uniform nip pressures from end to end and in which thedynamic forces tending to cause the faster rotating of these rolls towhip are counter balanced, even though the drafting rolls are relativelylong and small in diameter.

In a preferred form of the apparatus, the deflection forces on eachslower moving drafting roll is counter balanced by a supporting rollerplaced centrally along the length of the roll, with the two supportrollers for the drafting rolls of each pair being disposed in a planepassing through the centers of the two drafting rolls of the pair. Thedynamic whipping forces, with respect to the faster moving draftingrolls, are also balanced by support rollers centrally located along thelength of each of the faster rotating rolls; however, each of the fastermoving rolls is provided with a plurality of such support rollers, andthese support rollers are arcuately spaced about the periphery of eachof these drafting rolls. Assuming that two support rollers for each ofthe faster drafting rolls are used, these support rollers may be placed,for example, at 10 oclock and 2 oclock with respect to the upper one ofa pair of the fast rotating rolls, and the support rollers for thebottom one of the pair may be placed at 4 oclock and 8 oclock, thesepositions being located with respect to a plane passing through thecenters of the upper and lower fast rotating drafting rolls.

The invention consists of a novel construction to be hereinafterdescribed and claimed for carrying out the above stated objects, andsuch other objects, as will be apparent from the following descriptionof a preferred form of the invention, illustrated with reference to theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of adrafting frame to gether with gearing for driving the fluted draftingrolls of the apparatus without showings (for better illustration of thebasic drafting frame) of the support rollers for the drafting rollsconstituting an important feature of the invention;

FIG. 2 is a sectional view of the two fluted drafting rolls and takenfrom line 2-2 of FIG. 1;

FIG. 3 is a side elevational view of a certain drive gearing of theapparatus and taken from line 3-3 of FIG. 1;

FIG. 4 is a sectional view showing certain other gearing of theapparatus and taken from line 44 of FIG. 1;

FIG. 5 is a top plan view of the gearing shown in FIG. 4 and taken fromline 5-5 of FIG. 4;

FIG. 6 is a fragmentary top plan view of the fluted drafting rolls ofthe apparatus and showing support rollers for each of the top draftingrolls;

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawingsand in particular to FIGS. 1 and 7, the illustrated drafting apparatusmay be seen to comprise upper drafting rolls 10, 11, 12, 13 and 14 andlower drafting rolls 15, 16, 17, 1'8 and 19. The

roll is disposed directly below the roll 10 and has a nip with the roll10 so as to form a pair of cooperating drafting rolls, and the same istrue with respect to the rolls 11 and 16, the rolls 12 and 17, the rolls13 and 18, and the rolls 14 and 19, respectively. The rolls 10 to 14rotate progressively at greater speeds, and the lower rolls 15 to 19each rotates at the same speed as the upper roll with which the lowerroll has a nip. Each of the rolls 10 to 19 is longitudinally fluted andthe pairs of rolls have their flutes intermeshing; and preferably thefaster rotating ones of the rolls 10 to 19 are provided with a greaternumber of finer flutes than the slower rotating rolls. The rolls 10 to19 are mounted in a frame 20 in any suitable manner, such as, forexample, in the manner indicated in U.S. Pat. 3,203,051 issued on Aug.31, 1965, to I. R. Whitehurst.

The lower rolls 15 to 19' are driven at progressively higher speeds, andthis may be accomplished by means of any suitable gearing, such as, forexample, the gearing that is illustrated in FIGS. 1, 3, 4 and 5. Each ofthe upper rolls 10 to 14 rotates along with the lower roll with which itforms a pair due to the intermeshing relationship of the upper roll tothe lower roll of the pair, and the upper and lower rolls of each pairare held in nipped relationship by means of suitable mechanismassociated with the frame 20. This nipped relataionship is preferablysuch that there is a slight clearance between the top and bottom rollsof each pair when no fibers are passed through the drafting apparatus.

The roll 19 is the fastest rotating lower roll, and this roll has a spurgear 21 fixed to it which is in mesh with a larger gear 22 mounted on acountershaft 23. A gear 24 is fixed to the gear 22 and meshes with alarger gear 25 which is fixed with respect tothe intermediate lowerdrafting roll 17. The gear 21 is driven from any suitable prime mover(not shown), and the roll 17 is driven in the same direction of rotationbut at a slower speed by means of the gear train 21, 22, 24 and 25 dueto sizes of these gears.

The gear train 21, 22, 24, 25 is located on one side of the frame 20;and gearing for driving rolls 15, 16 and 18 is located on the other sideof the frame 20. The latter gearing comprises gears 26, 27, 28, 29 andwhich are respectively fixed on the rolls 19, 18, 17, 16 and 15. Thegears 26, 28 and 30 are located in line close to the frame 20; and thegears 27 and 29 are located in line but out of line with gears 26, 28and 30 and more remote from the frame 20. A pair of gears 31 and 32 arefixed together and are disposed on a countershaft 33 with the gear 31 inmesh with the gear 26 and the gear 32 in mesh with the gear 27. The gear26 is smaller than the gear 31 and the gear 32 is smaller than the gear27; and, therefore, the drafting roll 18 is driven from the draftingroll 19 in the same direction but at a slower speed.

A pair of gears 34 and 35 are fixed together and are rotatably disposedon a countershaft 36. The gear 34 is in mesh with the gear 28 and thegear 35 is in mesh with the gear 29; and, since the gear 28 is smallerthan the gear 34 and since the gear 35 is smaller than the gear 29, thedrafting roll 16 is driven from the drafting roll 17 at a slower speedthan the roll 17,

A pair of gears 37 and 38 are fixed together and are rotatably disposedon a countershaft 39. The gear 37 is in 4 mesh with the gear 29, and thegear 38 is in mesh with the gear 30; and, particularly since the gear 37is larger than the gear 29, the drafting roll 15 is driven in the samedirection as and at a slower speed than the drafting roll 16.

The rolls 10 and 15, which are the slowest rotating fluted draftingrolls in the apparatus, are respectively supported by rollers 40 and 41(see FIGS. 6 and 7). The centers of the rolls 10 and 15 are in avertical plane 42, and the centers of the support rollers 40 and 41 arelikewise in this plane. The support rollers 40 and 41 are locatedapproximately in the center of the rolls 10- and 15, that is, midwaybetween the ends of the rolls 10 and 15. The successively faster movingroll pairs 11, 16 and 12, 17 are supported centrally of their ends inthe same manner as the rolls 10 and 15, the rolls 11 and 16 beingrespectively supported by support rollers 43 and 44 and the rolls 12 and17 being respectively supported by support rollers 45 and 46.

The lower drafting roll 18 of the roll pair 13, 18 is supported by meansof rollers 47 and 48, and the upper roll 13 of this pair is supported byrollers 49 and 50. The planes of the support rollers 47 and 4 8 are outof alignment with respect to each other but both of the rollers 47 and48 are disposed approximately midway between the ends of the draftingroll 18; and the support rollers 49 and 50 for the upper drafting roll13 are arranged in the same manner with respect to each other and withrespect to the drafting roll 13. The centers of the rollers 47, 48, 49and 50 are disposed on opposite sides of a plane 51 passing through therespective centers 52 and 53 of the drafting rolls 13 and 18, therollers 47 and 48 being respectively positioned approximately at the 8oclock and 4 oclock positions with respect to the center 53 of the roll18, and the rollers 49 and 50 being positioned approximately at the 10oclock and 2 oclock positions with respect to the center 52 of the roll13. Each of the support rollers 47 and 48 thus provides a componentforce tending to hold the roll 18 against movement along a planeperpendicular to the plane 51, and the same is true of the supportrollers 49 and 50 with respect to the drafting roll 13.

The fastest rotating drafting rolls 14 and 19 of the draftinginstallation are supported in the same manner as are the rolls 13 and18, by means of support rollers 54 and 55 for the lower roll 19 and bymeans lof rollers 56 and 57 for the roll 14 (see FIGS. 6, 7, 8 and 9).The rolls 54 and 55 are disposed at the 8 oclock and 4 oclock positionswith respect to the roll 19, and the rolls 56 and 57 are disposed at the10 oclock and 2 oclock positions with respect to the roll 14.

It is desirable that the upper rolls 10, 11, 12, 13 and 14 be removed attimes from the drafting apparatus, such as for example, to relieveplug-ups of sliver passing between the drafting rolls; and, therefore,the rollers 40, 43, 45, 49, 50, 56 and 57 are mounted so that they maybe elevated to allow the upper drafting rolls 10 to 14 to be removed. Inthis connection, it may be mentioned that the upper drafting rolls 10 to14 each preferably is rotatably mounted in open grooves provided in theframe 20, such as for example, as shown in U.S. Pat. 3,203,051previously mentioned to allow the upper rolls to be removed from theframe 20. In order to illustrate the manner in which the rollers 40, 43,45, 49, 50, 56 and 57 may be mounted, FIGS. 8 and 9 may be referred toshowing the mounting apparatus for the rollers 56 and 57. The rollers 56and 57 are carried by a cage assembly 58 which is rotatably disposedabout a shaft 59 that is fixed at its opposite ends in the frame 20'. Anair cylinder 60 is connected to the assembly 58 and is suitablysupported with respect to the frame 20 so that the assembly 58 androllers 56 and 57 may be held in their positions illustrated in FIGS. 8and 9 and the rollers 56 and 57 may be swung upwardly along with theassembly 58 so as to allow the drafting roll 14 to be removed from thedrafting frame.

The lower rolls 41, 44, 46, 47, 48, 54 and 55 may be,

mounted with respect to the frame 20 in the same manner as the upperrollers except that there is generally no need to move the lower rollersout of their operative positions supporting the respective rolls 15 to19; and, therefore, roller holder assemblies corresponding to theassembly 58 need have no air cylinder releasably holding them inposition and instead rigid support bars may be provided for holding theroller supporting assemblies in operative position.

In operation, the fastest rotating or final drafting rolls 14 and 19 ofthe drafting apparatus may be driven at, for example, 1360 r.p.m. Theroll pairs prior to the pair 14, 19 are. successively driven at slowerspeeds, and the slowest rotating rolls and 15, which are the first rollsin the series of drafting rolls of the apparatus, may, for example, bedriven at of the speed of the rolls 14 and 19. Slivers 58 of fibrousmaterial, such as for example, fibers of rayon or nylon, are drawn intothe drafting apparatus between the rolls l0 and 15; and there may, forexample, be two to four slivers per inch of length of the rolls 10 and15. The slivers are compressed between the rolls 10 and 15, and theserolls 10 and 15 thus have a force from the slivers tending to force therolls 10 and 15 apart. The fibrous material thereafter passessuccessively between the rolls 11, 16, 12, 17, 13, 18 and 14, 19, andeach successive pair of these rolls rotate faster than the precedingpair so that the fibrous material is drafted or stretched and individualfibers are drawn more closely into the longitudinal direction ofmovement. At the same time, the fibers move laterally and spread sothat, as he fibrous material passes out from between the rolls 14 and19, there is a substantially uniform web.

The maximum desirable diameters of the drafting rolls 10 to 19 and alsothe maximum desirable spacing between the pairs of these drafting rollsare dependent on the length of fibers in the fibrous material to bedrafted, if the proper drafting effect is to be attained. The fibers ofthe fibrous material may be, for example, about 2% inches in length;and, in this case, the diameters of the drafting rolls should preferablybe no more than 2% inches and the spacing between the drafting rollpairs should preferably be no more than 2 /2 inches. Using thesedimensions, there thus is only a slight clearance between successivepairs of the drafting rolls. If relatively long drafting rolls 10 to 19are used, for example, 60 inches in length, in lieu of 15 or 20 inchlength rolls conventionally used, the drafting rolls, if of a 2% inchdiameter, become unduly flexible and limber, particularly when they aremade in lengths greater than about inches; and this is true even thoughhigh quality steel is used in the manufacture of the drafting rolls.Since the rfiber length more or less dictates the diameter of thedrafting rolls and of the spacing between the drafting roll pairs, it isnot possible to remedy this condition of undue flexibility by increasingthe diameters of the drafting rolls. Therefore, according to the presentinvention, the supporting rollers 41 to '45 and 48 to 56 have beenprovided for supporting the drafting rolls 10 to 29 to overcome theeffects of the undue flexibility of the drafting rolls, which effectsare primarily encountered with rolls having a relatively high ratio oflength to diameter, such as at least 20 to 1, based on the above stateddimensions of 40 inch roll length between lateral supports and 2%. inchroll diameter.

The slower rotating drafting rolls 10, 11, 12, 15, 16 and 17, all ofwhich rotate at speeds less than a predetermined speed, do not haverelatively great dynamic stresses tending to move them out of a uniformnipped relationship in the roll pairs; however, the slivers 58 passingbetween these slower rotating rolls have appreciable thickness, andthese rolls therefore tend to deflect or how outwardly with respect toeach other under the static forces due to the slivers 58. These rollshave, therefore, been braced by the support rollers 41, 42, 43, 44, and46 which lie directly in the planes in which the centers of 6 thedrafting rolls are disposed, for example, in the plane 42 of the centersof the rolls 10 and 15. These centrally disposed supporting rollers 40and 41 thus take the deflection forces and maintain substantiallyuniform nips between these pairs of rolls.

The forces on the other higher speed drafting rolls 13, 14, 18 and 19'tending to move them out of perfectly straight condition are primarilydynamic due to the highspeeds of rotation. The thickness of sliverbetween these fast moving rolls is considerably reduced, and there is noappreciable force tending to bow the drafting frame rolls apart, butthese fast rotating drafting rolls rather tend to oscillate, flex andwhip due to their high speeds; and, even though these high speeddrafting rolls are practically perfectly balanced, they still have acritical speed at which they tend to whip. At this critical speed, thereis a resonant condition which is dependent on the modulus of elasticityof the material from which the drafting rolls are made, the length ofthe drafting rolls between supports, the speed of the rolls and the rolldiameters. This critical speed is approached at the speeds contemplatedfor these high speed rolls; and any such whipping action, of course,will change the thickness of the nips between these high speed rollpairs and will produce a fibrous product that is non-uniform andtherefore unsatisfactory.

The supporting rollers 47, 48, 49, 50, 54, 55, 56 and 57, which arearcuately spaced about the particular drafting rolls that the rollerssupport, such as at the 10 oclock, 2 oclock, 4 oclock and 8 oclokpositions previously described, have the effect of preventing thiswhipping motion of the high speed drafting rolls due to the fact thatthese rollers exert a restraining force on the high speed drafting rollsin the direction in which the web moves, that is, perpendicular to theplanes, such as the planes 42 and 51, passing through the centers of thepairs of drafting rolls. With respect to either pair of high speeddrafting rolls, the rolls 13 and 18 or the rolls 14 and 19, it will beobserved that the supporting rollers are disposed not only to each sideof the drafting rolls but are also disposed above and below the draftingrolls so that whipping action in any direction, upwardly and downwardlyor else in the direction in which the web rnoves, is thereby prevented.

It will be observed that I have provided drafting roll supportingrollers in positions which are commensurate with the stresses that theparticular drafing rolls have on them. The slow speed rolls 10, 11, 12,15, 16 and -17 have forces which are more or less static and are in theplane containing the centers of the drafting rolls, being due to theslivers passing between the rolls and tending to force them apart. Ihave, therefore, provided the supporting rollers 41 to 46 which arelocated in these planes in which the forces occur, and which thus, witha minimum of material, take the particular forces that are effective onthese particular draft-ing rolls. With respect to the high speeddrafting rolls 13, 14, 1 8 and 19, in which the forces are dynamic,tending to cause whipping in all directions, I have braced the draftingrolls from all sides around the quadrant, namely at the 10 oclock, 2oclock, 4 oclock and 8 oclock positions previously described. Theparticular supports, therefore, that I have provided are thuscommensurate with the particular forces that are effective on thedrafting rolls tending to disrupt a uniform nip between them.

I wish it to be understood that the inveniton is not 10 be limited tothe specific contsructions, arrangemens and devices shown and described,except only insofar as the claims may be so limited, as it will beunderstood to those skilled in the art that changes may be made withoutdeparting from the principles of the invention. I also wish it to beunderstood that the above abstracts of the disclosure shall not be usedfor interpreting the claims or in any way to limit their scope.

I claim as my invention:

1. Apparatus for drafting fibrous material comprising a frame, aplurality of fluted drafting rolls rotatably supported at laterallyspaced points within said frame, the ratio of the length of each of thedrafting rolls between said points relative to its diameter beinggreater than about 20 to 1, said drafting rolls being arranged in aseries of spaced pairs including a first roll pair and a final roll pairwith the drafting rolls of each pair having a nip between them and thedrafting roll pairs being so arranged that the fibrous material may passsuccessively between the roll pairs in the series, means for drivingsaid drafting rolls such that successive drafting roll pairs in theseries are driven at successively higher speeds with respect to thespeed of said first roll pair and said final roll pair is driven at suchspeed that the rolls tend to whip and deflect in a plane substantiallyparallel to the passage of the material, a supporting roller meanspositioned medially of the ends; of each drafting roll of said firstroll pair for exerting a restaining force thereon to minimizedeflections thereof in a plane passing substantially through the centersof both of the drafting rolls of said first roll pair and separation ofthe drafting rolls of said first roll pair due to the passage of fibousmaterial therebetween, and a pair of rollers for supporting each of thedrafting rolls of said final roll pair positioned medially of the endsthereof and having their centers on opposite sides of a plane passingthrough the centers of both of the drafting rolls of said final rollpair for exerting a restraining force thereon to minimize deflectionsthereof in a plane substantially parallel to the passage of the materialand for absorbing whipping stresses in the drafting rolls of said finalroll pair.

2. Apparatus according to claim 1 for drafting fibrous material in whichsaid supporting roller means positioned medially of the ends of eachdrafting roll of said first roll pair comprises a supporting rollerhaving its center substantially in a plane passing through the centersof both of the drafting rolls of said first roll pair.

3. Apparatus according to claim 1 for drafting fibrous material in whichsaid series of spaced pairs of drafting rolls includes a first rollpair, a final roll pair, and an intermediate roll pair prior to saidfinal roll pair, and further having a pair of rollers for supportingeach of and for absorbing whipping stresses in the drafting rolls ofsaid intermediate roll pair.

4. Apparatus according to claim 3 for drafting fibrous material in whichadjacent supporting rollers for said intermediate and final roll pairsare staggered to avoid interference therebetween.

References Cited UNITED STATES PATENTS 2,854,700 10/1958 Caspari et al1965X FOREIGN PATENTS 372 1855 Great Britain 19-400 3,881 1883 GreatBritain 19l05 4,557 1892 Great Britain 19128 706,023 3/ 1954 GreatBritain l9236 DORSEY NEWTON, Primary Examiner US. Cl. X.R.

